Billions of dollars are spent annually on online advertising in the United States alone with the hope that such marketing will influence viewers to purchase product. In fact, online advertising is a core source of income for many Internet-based companies, both large and small, and the anticipated or estimated effectiveness of these online advertisements in influencing viewers to transact with merchants is often cited as justification for such marketing. However, current methods for correlating advertisements with user purchases are generally poorly suited to determine a real effectiveness of a particular advertisement in influencing a user to initiate a transaction.